Tool for leveling protuberances in sheet metal



Oct. 17, 1950 -ws 2,526,380

TOOL FOR LEVELING PROTUBERANCES IN SHEET METAL Filed Feb. 24, 1948 2 Sheets-Sheet 1 grwvvfiml ALBERT L. MATHEWS Oct. 17, 1950 A. L. MATHEWS 2,526,380

, TOOL FOR LEVELING PROTUBERANCES IN SHEET METAL Filed Feb. 24, 1948 2 Sheets-Sheet 2 awe/WM: ALBERT L. MATHEWS Patented Oct. 17, 1950 UNITED STATES QFFI'CE TOOL FOR LEVELING PROTUBERANCES IN SHEET METAL 1 Claim.

This invention relates to a pneumatic hammer which is particularly adapted for use in beating out very small depressions in the surfaces of sheet metal such as in automobile body work.

Heretofore, it has been accepted practice to hold the pointed end of a sharp instrument, such as an ice pick, against a small convex surface of sheet metal which, of course, was concave on the opposite side. The other end of the ice pick was then tapped lightly and repeatedly by a hammer; not with enough force to cause the pointed end of the ice pick to penetrate the sheet metal, but to cause minute outward projections, not unlike coarse sandpaper, on the said opposite surface of this sheet metal. The rough surface is then filed off and prepared in the usual manner for painting. This procedure is extremely difficult in confined areas and in many instances requires the removal of upholstery and other obstructions when repairing surfaces such as automobile door panels. I

It is therefore an object of this invention to provide a tool having a reciprocating plunger therein, the movement of said plunger being controlled by means remotely disposed from the plunger and said plunger being disposed within a housing which may be held in one hand thus permitting access to very confined areas.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds, when taken in connection with the accompanying drawings, in which:

Figure l is an elevation showing the tool with the plunger in engagement with a small portion of sheet metal and showing a valve and a compressed air tank which are associated therewith;

Figure 2 is a vertical sectional view taken along the line 22 in Figure 1 omitting the sheet metal;

Figure 3 is a vertical sectional view taken along the line 33 in Figure 1;

Figure 4 is an elevation being partly in section and taken substantially along the line 44 in Figure 1;

Figure 5 is a vertical sectional view of the central portion of Figure 3 with the valve in a different position;

Figure 6 is a plan view, with parts in section, and taken along the line 36 in Figure 3.

Referring more specifically to the drawings, the numeral [0 indicates a source of compressed air, such as a motor compressor or a compressed air tank, having connected thereto as at H, by a suitable fitting 9, a .fiexible hose I2 which extends upwardly in Figure 1 and the other end of .the hose l2 has a fitting 8 which is threadably mounted in a threaded bore 1 in a conventional Schrader blow gun valve I5, such as that shown in United States Letters Patent No. 1,957,567 and is described here as a means to clearly define the 2 action of this invention. However, there are many types of valves which could be used in association with this invention and it is not desired to confine the invention to this particular valve.

By referring to Figure 3, it may be observed that the valve l5 has a port hole l6 for theingress of air from the source of compressed air and the air will pass through this port hole I6 into a chamber H in which is mounted,.-for. vertical sliding movement therein, a disk l8, the lower end of which is engaged by the upper end of a compression spring Hi, the :lower :end' of which engages the bottom of the chamber l7.

Integral with and extending from the uppermost surface of the disk [8 is a stem 22 which tapers inwardly toward its upper endiand this portion 22 extends upwardly through an opening 23 in a valve seat 24. The topmost surface of the stem 22 is engaged bya disklike portion 25 which has integral therewith and extending upwardly therefrom, a shaft 26 whichhas integral therewith a tumb-press head 2! and disposed immediately below the thumb-press head 2'! is a resilient rubber washer 30.

The shaft 26 extends upwardly through and slidably penetrates a ferrule 31 having a plurality of vertically disposed bores 32 therethrough which are disposed around the shaft 26. It may be observed in Figure 3, that the compression spring H has urged the thumb-press head 21 upwardly and the disk portion 25 is resting against the top end of a bore 33 in the lower surface of the ferrule 3!. It is obvious that with the head 21 in this uppermost position, the disk 18 .will have passed above the port hole l6 and thus the air coming from the source of compressed air It] through the flexible hose l2 will not be able to pass through the valve l5. However, when the thumb-press head 21 is moved downwardly from the position shown in Figure 3 to the position shown in Figure 5, the disk [8 will permit air'to pass through the port hole I6 and upwardly and into the chamber I! and through the opening 23 and thus the air will pass through an opening 35 which is adjacent the lower end of the ferrule 3|. The air will pass through the opening 35 into a bore 36 which is threaded at its open end as at 44 in which an elbow 3'! is threadably mounted. Connected to the other end of elbow 31 is one end of a union 38. The other end of the union 38 is threadably connected to a fitting 34 on one end of a flexible hose 40 which extends upwardly and has a fitting 4i connected to a'downturned portion 42 (Figure 1) of a cylinder base 43. The cylinder base 43 and the downwardly projecting portion 42 are parts of the tool broadly designated at 45. The downturned portion 42 and the cylinder base 43 have interconnecting bores 49 and 3 39 (Figure 2) therein for passage of air between the flexible hose 40 and a cylinder to be presently described.

The cylinder base d3 threadably engages one end of a cylinder 45 and secured to the other end of the cylinder 46, by any suitable means such as welding 48, is a cylinder head 41. The cylinder head 41 is penetrated by a plurality of bores 50 and the outer surface of the cylinder head 4? has an annular groove 5| therein which also has an annular countergroove 52 adjacent thereto and disposed in the outer surface of the cylinder head 47. The countergroove 52 forms a shoulder 53 against which a screen wire member 55 is dis posed and the outer edges of the cylinder head M are crimped inwardly as at 56 to confine the screen wire 55 against the shoulder 53. The screen wire covers the annular groove 5 i.

Extending outwardly from the cylinder head i! and disposed in the center thereof is a portion 51 having a bore E therethrough which slidably receives a plunger iii. The plunger 6! has a collar 62 mounted thereon and the collar 32 engages the outward end of the portion of the head end 41 thus limiting inward movement of the plunger 6i. The plunger (H has a bore 6 3 therein in which a pin 55, having a pointed end $3, is mounted. The pin 55 is confined in the bore 64 by a set screw E l which loosely penetrates the collar 62 and threadably penetrates the plunger El and not only secures the pin 65 in the bore 64, but also secures the collar E2 on the end of the plunger 6!.

The plunger 5! which extends inwardly into the cylinder 48 and has a head portion 68 integral therewith which is engaged by a compression spring Til which is disposed around the' plunger 6|, extends to and engages the inner surface of the head end il'. Disposed around the compression spring 10, as Well as the plunger BI and the headed portion 68 of the plunger 65, is a larger compression spring l2 which also engages the inner surface of the cylinder head 4? and extends to the right, as observed in Figure 2, and rests in an annular groove Tl in a piston 75. The groove 11 defines a projecting portion 56 in the center of the piston 75 which is encircled by one end of the spring 12.

When air is admitted through the chamber 36 of the valve l5 as heretofore described, it will continue through the elbow 3! and the pipe iii to the cylinder base 43 of the tool 45 and thus the piston will be urged to the left as observed in Figure 2. The portion it then engages the head portion 68 of the plunger 6i and thus moves the plunger 6! outwardly relative to the cylinder 46. Upon releasing the thumb-press head 2'! the compression spring I9 will urge the parts from the position shown in Figure 5 to the position shown in Figure 3 and thus the air which has formerly entered the cylinder 45 will return through the pipe 4!! and into the bore and through the port hole 35. The air will then escape upwardly through the bores 32 in the ferrule 3|. This will permit the piston E5 to be urged to the right, as observed in Figure 2, by the compression spring i2 and will also permit the plunger 6! to be urged to the right as observed in Figure 2, by the compression spring "#2 and will also permit the plunger 6-! to be urged to the right as observed in Figure 2 by the compression spring 10.

Thus by holding the tool in th one hand, the pointed end 66 of the pin may be held against an inwardly projecting portion 80 of a sheet metal member 8i and by rapidly reciprocating the thumb-press head 27 with ones thumb as the valve E5 is held in the other hand, the point 66 of the pin 55 will gradually move the projecting portion of the sheet metal member 8| outwardly by the reciprocatory action thus imparted thereto and the sheet metal will be left relatively smooth at which time a file may then be used against the exterior surface of the same for the final working of the metal as is conventional practice.

In the drawings and specification, there has been set forth a preferred embodiment of the invention, and although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claim.

I claim:

In a pneumatic means for leveling protuberances in sheet metal, a source of compressed air, a cylinder, a hose leading from the source of compressed air to one end of the cylinder, a manually movable valve disposed in the hose, spring means for holding the valve in one position and the valve being manually movable to another position to allow air under pressure to flow into the cylinder and being movable to another position to cut oil the flow of air under pressure into the cylinder and to allow escapernent of the air therefrom, said cylinder comprising a reciprocable piston, said piston having an annular groove therein, said groove defining a projecting portion on the center of the piston, a compression spring having one end mounted in the annular groove, the other end of the compression spring being mounted against the other end of the cylinder, a plunger mounted in the cylinder and extending from one end thereof, a pointed member carried by the plunger for engaging a protuberance, admission of compressed air into the cylinder serving to move the projecting portion of the piston into contact with the plunger to move the same outwardly with respect to the cylinder to cause the pointed member to engage the protuberance, the end of the plunger next to the piston being enlarged, a second compression spring surrounding the plunger and having one end resting against the enlarged head of the plunger and having its other end resting against the other end of the cylinder and tending to move the plunger to retracted position with respect to the cylinder, the compression spring disposed between the piston and the other end of the cylinder serving to return the piston to the said one end of the cylinder through which compressed air is admitted when the compressed air is cut off from the cylinder and vented from the cylinder by means of said valve.

ALBERT L. MATHEWS.

CES CIITED The following references are of record in the file of this patent:

UNITED STATES PA'IENTS Number Name Date 856,847 Connors June 11, 1907 1,047,658 Krueger Dec. 1'7, 19 -2 FOREIGN PATENTS Numb or Country Date 525,773 Great Britain Sept. 4, 1940 33,898 Norway Jan. 16, 1922 

